The metabolic fluxes through the central carbon pathways were calculated for the genus Bacillus separately for the enzymes serine alkaline protease (SAP), neutral protease (NP) and alpha-amylase (AMY) on five carbon sources that have different reduction degrees (gamma), to determine the theoretical ultimate limits of the production capacities of Bacillus species and to predict the selective substrate for the media design. Glucose (gamma=4.0), acetate (gamma=4.0), and the TCA cycle organic-acids succinate (gamma=3.5), malate (gamma=3.0), and citrate (gamma=3.0) were selected for the theoretical analyses and comparisons. A detailed mass flux balance-based general stoichiometric model based on the proposed metabolic reaction network starting with the alternative five carbon sources for the synthesis of each enzyme in Bacillus licheniformis that simulates the behaviour of the metabolic pathways with 107 metabolites and 150 reaction fluxes is developed. Highest and lowest specific cell growth rates (&mgr;) were calculated as 1.142 and 0.766h(-1), respectively, when glucose that has the highest degree of reduction and citrate that has the lowest degree of reduction were used as the carbon sources. Highest and lowest SAP, NP and AMY synthesis rates were also obtained, respectively, when glucose and citrate were used. Metabolic capacity analyses showed that the maximum SAP, NP, and AMY synthesis rates were, respectively, 0.0483, 0.0215 and 0.0191mmolg(-1)DWh(-1) when glucose uptake rate was 10mmolg(-1)DWh(-1) and specific growth rate was zero. The amino acid compositions and the molecular weights of the enzyme influence the production yield and selectivity. For SAP and NP oxaloacetate and pyruvate, for AMY oxaloacetate appear to be the critical main branch points. Consequently, for SAP and NP syntheses the fluxes towards the alanine group and aspartate group, and for AMY synthesis the flux towards the aspartate group amino acids need to be high. The results encourage the discussion of the potential strategies for improving productions of SAP, NP and AMY.

中文翻译：

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碳源影响芽孢杆菌属生产工业酶的代谢能力：丝氨酸和中性蛋白酶和 α-淀粉酶的理论分析

分别针对具有不同还原度 (γ) 的五种碳源上的丝氨酸碱性蛋白酶 (SAP)、中性蛋白酶 (NP) 和 α-淀粉酶 (AMY) 计算了芽孢杆菌属通过中央碳途径的代谢通量，确定芽孢杆菌物种生产能力的理论极限并预测培养基设计的选择性底物。选择葡萄糖 (γ=4.0)、醋酸盐 (γ=4.0) 和 TCA 循环有机酸琥珀酸盐 (γ=3.5)、苹果酸盐 (γ=3.0) 和柠檬酸盐 (γ=3.0) 进行理论分析和比较. 基于拟议的代谢反应网络的详细质量通量平衡的一般化学计量模型，从替代的五种碳源开始，用于合成地衣芽孢杆菌中的每种酶，该模型模拟具有 107 种代谢物和 150 种反应通量的代谢途径的行为. 当使用还原度最高的葡萄糖和还原度最低的柠檬酸盐作为碳源时，最高和最低的特定细胞生长率 (&mgr;) 分别计算为 1.142 和 0.766h(-1)。当使用葡萄糖和柠檬酸盐时，还分别获得了最高和最低的 SAP、NP 和 AMY 合成率。代谢能力分析表明，最大 SAP、NP 和 AMY 合成速率分别为 0.0483、0.0215 和 0。0191mmolg(-1)DWh(-1) 当葡萄糖摄取率为 10mmolg(-1)DWh(-1) 且比增长率为零时。氨基酸组成和酶的分子量影响产量和选择性。对于 SAP 和 NP 草酰乙酸盐和丙酮酸盐，对于 AMY 草酰乙酸盐似乎是关键的主要分支点。因此，对于 SAP 和 NP 合成朝向丙氨酸组和天冬氨酸组的通量，而对于 AMY 合成，朝向天冬氨酸组氨基酸的通量需要很高。结果鼓励讨论改进 SAP、NP 和 AMY 产量的潜在策略。对于 SAP 和 NP 草酰乙酸盐和丙酮酸盐，对于 AMY 草酰乙酸盐似乎是关键的主要分支点。因此，对于 SAP 和 NP 合成朝向丙氨酸组和天冬氨酸组的通量，而对于 AMY 合成，朝向天冬氨酸组氨基酸的通量需要很高。结果鼓励讨论改进 SAP、NP 和 AMY 产量的潜在策略。对于 SAP 和 NP 草酰乙酸盐和丙酮酸盐，对于 AMY 草酰乙酸盐似乎是关键的主要分支点。因此，对于 SAP 和 NP 合成朝向丙氨酸组和天冬氨酸组的通量，而对于 AMY 合成，朝向天冬氨酸组氨基酸的通量需要很高。结果鼓励讨论改进 SAP、NP 和 AMY 产量的潜在策略。